Implantable medical devices (IMDs), such as pacemakers, cardioverter defibrillators, drug pumps, neurostimulators, and the like, include electronic circuitry enclosed within a hermetically sealed housing. The housing is typically formed of two shield halves, referred to herein as a case and a cover, that are welded together. One method for assembling an IMD such as an implantable cardioverter defibrillator (ICD) involves setting a battery and capacitor in the case, placing a hybrid circuit over the battery, and placing any additional components, such as communication circuitry, over the capacitor. All necessary electrical connections can then be made between the hybrid circuit and other ICD components stacked together in the case. After electrical connections are made and any testing is performed, the cover is placed over the case and the housing welded closed. This method of assembly can be generally referred to as a “top-down” assembly method since all IMD components are stacked together in the case and the cover is then placed over the case. Other assembly methods involve assembling and electrically coupling all of the circuitry and components together then placing the assembled component into the housing as one unit and closing the housing.
In some circumstances, however, it is desirable to include components mounted to an interior surface of the IMD housing. For example, a piezoelectric transducer used to generate an audible patient alert may be mounted to an interior surface of the housing to cause the housing to resonate, thereby improving the patient alert function of the IMD. Methods are needed for assembling an IMD having electrical components mounted to an interior surface of the housing which still allows a top-down assembly of the device.